(1) Field of the Invention
The present invention relates to an electric junction box, in which an internal circuit is constructed by using a metal wire rod having a quadrangular cross section, and a process for producing the electric junction box.
(2) Description of the Related Art
In a conventional Junction box, a band plate-shaped busbar or a round-shaped insulator-coated electric wire is arranged in a case or cover made of synthetic resin so as to form a circuit, and then an electric component such as relay and fuse, an electronic component such as an electronic unit, and an electric connector of an external wiring harness are connected to the circuit.
The busbar is punching-molded by pressing from an electrically conductive metal plate, has a rectangular shape that is wide in its cross section, and is bent in the width direction of the metal plate upon the punching in response to a form of the circuit. At necessary positions of the busbar, a terminal part having a male tab-shape is integrally formed standing up and down.
A plurality of busbars are arranged on an insulating board made of synthetic resin, a plurality of busbar wiring boards, each consisting of the insulating board and the busbars, are laminated, a terminal part of the busbar situated at a lower layer penetrates through a hole of the insulating board situated at an upper layer while a terminal part of the busbar situated at an upper layer penetrates through a hole of the insulating board situated at a lower layer, and each terminal part protrudes in a connector housing, toward a relay-mounting part or toward a fuse-mounting part of a case. The connector housing and the terminal constitute a connector. The terminal part is connected to the relay or the fuse through a relay terminal.
When an electric wire (hereinafter, wire) is used instead of a busbar or when a wire is used together with a busbar, the wire is arranged on the insulating board in a required form, for example, one plate-shaped terminal is pressure-welded or welded to the wire while an opposite terminal is made protrude in the connector housing or toward the relay-mounting part and so on. The opposite terminal is connected to a relay or a fuse through a relay terminal.
The busbar or the wire may be connected to a solenoid valve, various sensors or switches instead of a relay or fuse. For example, that is a case of an automatic gearing module of a motor vehicle, in which the module includes a function of the electric junction box.
However, in the conventional electric junction box described above, because the busbar should be punching-molded into various bent shapes in accordance with respective forms of the circuit, the mold for the molding must be renewed whenever the form of the circuit is changed, causing an increase in cost. Further, the busbar having a shape wider than that of a wire makes the circuit density limited, causing an increase in weight and size of the busbar wiring board and a case which receives the busbar wiring boards. Furthermore, although the busbar is capable of conducting a large current, the busbar is not suitable for a small current such as a signal current, in a case of which an insulator-coated electric wire having a small diameter is required, causing many man-hours for connecting a terminal to a wire by pressure-welding or welding.
It is therefore an objective of the present invention to solve the above problems and to provide an electric junction box and a process for producing the electric junction box, by which a cost for processing the busbar per a form of the circuit can be reduced, the man-hour for connecting a terminal to a wire can be reduced, the circuit density can be increased, or the whole structure can be lightweight and compact.
In order to attain the above objective, the present invention provides an electric junction box comprising:
an insulating board; and
a plurality of electrically conductive metal wire rods each having a square or nearly square shape in cross section, which are arranged on the insulating board,
wherein an end of the metal wire rods extends curvedly or straight forming a terminal part and at least a portion of the terminal part protrudes toward a housing of a body of the electric junction box.
With the construction described above, because the width of the metal wire rod is less than that of a conventional busbar, a circuit of the metal wire rod can be arranged on the insulating board with high density and the structure of the circuit can be lightweight and compact provided that the number of the circuits is the same as that in a busbar. Further, because the end of the metal wire rod is extended curvedly or straight, the terminal part can be easily formed. Furthermore, because the terminal part is protruded in the housing, a connector for connecting to a mating connector and a mount (connecting part) for a relay or fuse can be formed.
With the construction described above, the electric junction box can be easily securely mounted in a narrow space for mounting in a motor vehicle, for example. Further, because there is no need to use a mold for molding a terminal part standing up at the middle portion in the longitudinal direction of a busbar in case of the conventional busbar, the cost of the mold can be eliminated.
Preferably, the metal wire rod is cut to a suitable length, bent into a suitable shape, and arranged on the insulating board.
With the construction described above, the metal wire rod is bent according to the position of an electric component such as relay, fuse and sensor, an electronic component such as a memory, and a connector for connection, thereby effectively attaining an electric connection in the nearest distance. Further, the metal wire rod is cut to a suitable length and bent into a suitable shape at a specific position according to the form of the circuit, thereby enabling an easy response to a change in the circuit form. Furthermore, a period of time required from designing to completion of the electric junction box can be reduced.
Preferably, one terminal part of the metal wire rod protrudes toward the housing, while an opposite terminal part of the metal wire rod is connected to a component or a terminal or, alternatively, protrudes toward another housing.
With the construction described above, the one terminal part can function as a connector for connecting to a mating connector or a mount for a relay and fuse, while the opposite terminal part can function as a connection part for an electronic component or a part such as a sensor or, alternatively, a connector for connecting to a mating connector or a mount for a relay and fuse, thereby attaining various forms of the circuit connection. Further, the connection to various electric equipment or an auxiliary in a motor vehicle can be easily attained.
Preferably, a terminal is directly connected to a middle portion in the longitudinal direction of the metal wire rod.
With the construction described above, for example, a terminal for ground or a terminal for power supply is directly connected to the middle portion in the longitudinal direction of the metal wire rod not having a terminal part at one end or both ends or the metal wire rod having a terminal part at one end or both ends by welding and so on, thereby enabling joint connection among a plurality of the circuits and attaining various forms of the circuit connection. Further, many components and circuits in a motor vehicle can be connected compactly.
Preferably, the end of the metal wire rod is folded and compressed into a plate-shape, thereby forming the terminal part.
With the construction described above, the contact area of the terminal part can increase, thereby reducing the resistance for electric conduction to a mating terminal (female terminal) and enabling to easily correspond to a mating terminal having an existing shape (i.e. no need to change a shape of a mating terminal).
Preferably, the metal wire rod is subjected to tinning.
With the construction described above, the metal wire rod including the terminal part is prevented from being oxidized, thereby improving the electric conduction property of the terminal part (reducing the electrical resistance). Further, sliding property of the terminal part with respect to a mating terminal can be improved, thereby reducing the resistance force for insertion.
Preferably, the metal wire rod has 0.025 inches on a side.
With the construction described above, because the diameter of the metal wire rod is small, the circuit density can be increased and the structure can be compacted. Further, a small current such as a signal current can be supplied or grounded.
In order to attain the above objective, the present invention provides a process for producing an electric junction box comprising the steps of:
extending curvedly or straight an end of a plurality of electrically conductive metal wire rods having square or nearly square shape in cross section, thereby forming a terminal part;
arranging a plurality of the metal wire rods on an insulating board; and
protruding at least a portion of the terminal part toward a housing of a body of the electric junction box.
With the construction described above, because the width of the metal wire rod is less than that of a conventional busbar, a circuit of the metal wire rod can be arranged on the insulating board with high density and the structure of the circuit can be lightweight and compact provided that the number of the circuits is the same as that in a busbar. Further, because the end of the metal wire rod is extended curvedly or straight, the terminal part can be easily formed. Furthermore, because the terminal part is protruded in the housing, a connector for connecting to a mating connector and a mount (connecting part) for a relay or fuse can be formed.
With the construction described above, the electric junction box can be easily securely mounted in a narrow space for mounting in a motor vehicle, for example. Further, because there is no need to use a mold for molding a terminal part standing up at the middle portion in the longitudinal direction of a busbar in case of the conventional busbar, the cost of the mold can be eliminated.
Preferably, the metal wire rod is cut to a suitable length, bent into a suitable shape, and arranged on the insulating board.
With the construction described above, the metal wire rod is bent according to the position of an electric component such as relay, fuse and sensor, an electronic component such as a memory, and a connector for connection, thereby effectively attaining an electric connection in the nearest distance. Further, the metal wire rod is cut to a suitable length and bent into a suitable shape at a specific position according to the form of the circuit, thereby enabling an easy response to a change in the circuit form. Furthermore, a period of time required from a designing to a completion of the electric junction box can be reduced.
Preferably, one terminal part of the metal wire rod protrudes toward the housing, while an opposite terminal part of the metal wire rod is connected to a component or a terminal or, alternatively, protrudes toward another housing.
With the construction described above, the one terminal part can function as a connector for connecting to a mating connector or a mount for a relay and fuse, while the opposite terminal part can function as a connection part for an electronic component or a part such as a sensor or, alternatively, a connector for connecting to a mating connector or a mount for a relay and fuse, thereby attaining various forms of the circuit connection. Further, the connection to various electric equipment or an auxiliary in a motor vehicle can be easily attained.
Preferably, a terminal is directly connected to a middle portion in the longitudinal direction of the metal wire rod.
With the construction described above, a terminal for ground or a terminal for power supply is directly connected to the middle portion in the longitudinal direction of the metal wire rod not having a terminal part at one end or both ends or the metal wire rod having a terminal part at one end or both ends by welding and so on, thereby enabling joint connection among a plurality of the circuits and attaining various forms of the circuit connection. Further, many components and circuits in a motor vehicle can be connected compactly.
Preferably, the end of the metal wire rod is folded and compressed into a plate-shape, thereby forming the terminal part.
With the construction described above, the contact area of the terminal part can increase, thereby reducing the resistance for electric conduction to a mating terminal (female terminal) and enabling to easily correspond to a mating terminal having an existing shape (i.e. no need to change a shape of a mating terminal).